High salinity water purification processes and systems

ABSTRACT

A high salinity water purification system and process, including a forward osmosis system and a reverse osmosis or nanofiltration system. A concentrated brine of a zinc or iron complex combined with a salt or acid draws pure water across the FO membrane from the influent water. The diluted brine is pumped through a vessel holding an anionic adsorption media to remove the zinc or iron complex and the resultant brine is passed through the RO or nanofiltration system to obtain purified water and a concentrated brine stream. The adsorption media is regenerated by a rinse cycle using fresh water or water from the RO system, removing the zinc or iron complex adhered to the media. The resultant brine is stored and mixed with the output of the RO system.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority of U.S. Provisional Application No.62/777,602 filed Dec. 10, 2018, the entire contents of which applicationis incorporated herein by this reference.

BACKGROUND

One of the greatest challenges in water treatment is addressing highlevels of total dissolved solids (TDS) in water—basically: how todesalinate high TDS solutions. An emerging treatment technology is aprocess called “forward osmosis” (FO). This process differs fromtraditional reverse osmosis (RO). A traditional RO system pushes waterat high pressure through a membrane that essentially filters outdissolved minerals and produces a clean water stream and a concentratedsalt water stream. An FO system draws water across the membrane topurify it at a low pressure which reduces membrane fouling potential.With an RO, the higher the total dissolved solids of the water, thehigher the pumping pressure required and subsequently higher capital andoperating cost. The higher the overall total dissolved solids, the morecomplex and expensive the technical solution is.

One example of high TDS water is produced water, which is the water thatcomes from deep within the ground during the production of oil. As oilis brought out of the ground, water comes with it, which is thus called“produced water”. This water is very difficult to treat as it not onlyhas high levels of suspended solids and organics which can blind filtermedia and membranes, the water is also extremely high in dissolvedmineral salt content. Typically, the produced water is either hauled offsite to a disposal well or directly injected back into the ground fordisposal. Hauling the water is very costly and recent research indicatesthat injecting produced water back into injection wells can causeformation damage underground. For that reason, injection wells are beingreduced as a possible solution for waste disposal. The best solution isto minimize the amount of water put back into the ground and utilize anygood water for other industrial uses. Yet treating this water isextremely difficult.

BRIEF DESCRIPTION OF THE DRAWINGS

Features and advantages of the disclosure will readily be appreciated bypersons skilled in the art from the following detailed description whenread in conjunction with the drawing wherein:

FIG. 1 is a schematic diagram illustrating an exemplary embodiment of ahigh salinity water purification system and process.

FIG. 2 is a schematic diagram illustrating a second exemplary embodimentof a high salinity water purification system and process.

FIG. 3 is a schematic diagram illustrating a third exemplary embodimentof a high salinity water purification system and process.

FIG. 4 is a schematic diagram illustrating a fourth exemplary embodimentof a high salinity water purification system and process.

DETAILED DESCRIPTION

In the following detailed description and in the several figures of thedrawing, like elements are identified with like reference numerals. Thefigures are not to scale, and relative feature sizes may be exaggeratedfor illustrative purposes.

Water naturally wants to be in a state of equilibrium with respect tomineral content. An FO system utilizes a high TDS brine stream withstronger osmotic attraction than a waste stream to pull or draw purewater from the waste stream across a semipermeable membrane into thehigh TDS brine which thus dilutes it. The osmosis process will naturallycontinue until the osmotic attraction of the two streams areapproximately equivalent. The water that is pulled across the membraneand essentially dilutes the brine solution is then extracted from thebrine in various traditional treatment technologies, most commonlyreverse osmosis (RO) or nanofiltration. The pure water is produced inone stream from the RO and the other stream re-concentrates the brinesolution which then becomes the feed water back to the FO membrane. Theprocess is then repeated in a continual process.

The benefit of the FO system is the natural osmotic driving pressure ismuch lower than the pressure on a traditional RO membrane whichminimizes the fouling potential and subsequently reduces operating andmaintenance cost of the FO membrane system. A significant challenge withimplementing a forward osmosis system is how to efficiently process andre-concentrate extremely high TDS brines. This application describes lowcost, high efficiency methods of accomplishing high TDS brine drawre-concentration.

As noted above, the forward osmosis solution is highly advantageousbecause instead of pushing water across a membrane at high pressurewhich damages separation membranes (often beyond repair), FO “pulls ordraws” pure water across the membrane at low pressure through naturalosmosis and a brine solution which allows for easier and more effectivemembrane cleaning. This minimizes membrane fouling, whereas at highpressure RO membranes become fouled beyond repair. In the FO continualprocess, the pure water is produced and the concentrate stream from theRO system re-concentrates up the brine to continue pulling pure wateracross the FO membrane. However, in this FO brine recycling process,there are limitations as to how high a reverse osmosis system canre-concentrate the reject brine stream which limits how much water andwhat TDS of water an FO system can process. This new process technologyadvancement works in combination with the reverse osmosis system, oralternatively a nanofiltration system, to concentrate up the brinelevels to even higher levels than ever possible (excluding use of highenergy, high cost evaporators) which will help achieve greater watersavings at a lower operating and capital cost. As is well known in theart, nanofiltration uses a different membrane than RO, with a differentpore size to filter differently.

First Embodiment

A two-step water purification system and process is illustrated inFIG. 1. This embodiment employs a strong anionic base adsorption mediasuch as a resin or membrane to recycle a zinc or iron-based brine drawcombined with a sodium or magnesium-based brine draw (or acid) before ahigh salinity reverse osmosis or nanofiltration system for improvedbrine draw recycling performance and overall higher efficiency. Zinc oriron-based brines are unique in that they naturally have an extremelyhigh osmotic attraction which makes it beneficial as an FO brine draw.Zinc combined with a salt such as chloride can become “complexed” thusgiving it a natural selective attraction/affinity to the adsorptionmedia used in the purification process. This happens when the zinc oriron is in combination with a brine (sodium chloride as an example) orin combination with an acid such as hydrochloric acid. Either of thesetwo conditions makes the zinc into the form that the adsorption mediawill adsorb it, as described more fully below. The brine is insufficient concentration levels to complex the zinc or iron-basedcompound.

Zinc or iron-based brines are also unique in that there are anionicadsorption media with specific chemical affinity for zinc or iron-basedbrines. What makes this process even more unique is that the adsorptionmedia rinse “elutant” for these specific adsorption media, e.g. a resinor membrane, is plain water as opposed to another brine, acid, or basechemical. This makes rinse/flush cost of the adsorption media solutionextremely inexpensive and low energy.

In the following description of the first embodiment, zinc-based brinesare specifically described. it will be understood that iron-based brinesalso provide similar properties, and may alternatively be used in theprocess.

The first step in processing the brine from the FO system is to separatethe zinc-based brine from a sodium or magnesium-based brine, or acid(combined with pure water) using the adsorption media. The second stepis to process the sodium or magnesium-based brine (or acid) by purifyingit with a standard high salinity RO or nanofiltration system, thusproducing clean water and a re-concentrated brine. This re-concentratedbrine is then blended with the eluted zinc-based brine from theadsorption media rinse process. The combined brine solution is then fedback to the FO membrane and is used in a continual process.

The first step is done in a manner that uses a low-energy strong baseanion exchange media (resin or membrane) and fresh water for the flush.Utilizing fresh water for rinse is a key factor because it is extremelylow cost. There are many resins and membranes that can separate zincfrom resin (and membranes), but the more zinc to be removed, the moreflushing chemical needed which drives up operating cost significantly.The process of this embodiment by which the unique anionic media removeszinc involves the zinc-based brine being combined with another brine (oracid, such as HCl). This combined brine is in a multivalent form asopposed to a normal cationic phase, thus allowing the anionic adsorptionmedia to have a strong natural attraction to it. This strong attractionbinds or adheres the zinc to the anionic media. When the brine isremoved from the media and the media goes into the rinse or backwashcycle with fresh water, the accompanying brine is flushed from theadsorption media which reverses the multivalency of the zinc-basedbrine, and thus the zinc-based brine is easily removed from the resinwith just low total dissolved solids water. For this reason, the FObrine draw includes a blend of multiple brine solutions or thezinc-based brine is in combination with an acid (such as HCl).

This process utilizes a combined blend of brines or acid, to includezinc chloride, zinc bromide, ferric chloride, sodium chloride, sodiumbromide, and or magnesium chloride as primary examples (also to include:LiCl, CaCl 2, LiCl and HCl, HCl, KCl, CsCl, NH 4Cl, and HONH 3Cl). Theacid can be in solution with the zinc brine, but that is not necessary.Zinc chloride will attach to the adsorption media in the presence of anacid (such as HCl) or in the presence of another brine (such as NaCl).The acid would be in the brine or in place of the salt-based brine andconsistent throughout the FO system. To recover the costly brine drawmaterial and minimize waste, strong base anion adsorption media is usedto first separate the zinc bromide or zinc chloride brine salts thusleaving the effluent solution as only pure water combined with themagnesium chloride, sodium bromide, or sodium chloride brine draw to beprocessed by the high salinity RO or nanofiltration system. The strongbase anion adsorption media is flushed with clean, permeate water in afinal step of the process.

Referring now to the schematic of FIG. 1, a storage tank 1 holds theinfluent water for the process, which is a moderate TDS fluid, in therange of 30,000 to 150,000 ppm. The process water 3 is pumped by pump 2to provide a brine stream on the input side of FO membrane system 4. Theoutput side of the FO membrane has a concentrated brine draw containingZinc complex (or iron) and other salt brine. The concentrated brine drawis a high TDS fluid, in the range of 250,000 to 500,00 ppm. The highbrine draw fluid draws pure water across the FO membrane, leaving adiluted brine draw, which did not pass through the FO membrane,containing the Zinc complex (or iron) and other salt brine. With purewater having been drawn out by the FO system, the process water leavingthe FO system is a concentrated fluid, with a TDS in the range of300,000 to 500,000 ppm. The concentrated process fluid 5 is waste fromthe process, to be hauled off-site or otherwise disposed of.

The diluted brine draw 6 from the FO process is pumped by pump 7 throughvessel controls 23, including a valve system, to media vessels 8A, 8Bholding a Zinc or iron complex adsorption media, e.g. a strong anionicbase resin or membrane which has an extremely high osmotic attraction tothe zinc or iron-based complexes in the diluted brine draw. The zinc oriron complex adheres to the adsorption media, separating the zincbromide or zinc chloride so that the output 10 pumped from the vessels8A, 8B by pump 9 is essentially free of the zinc or iron complex. Thisdiluted brine draw 10 has NaCl, NaBr or MgCl₂ (or acid) and is amoderate TDS fluid, on the order of 30,00 to 150,000 ppm.

One example of the adsorption media suitable for the purpose is StrongBase Anion, Gel Type 1, Quaternary Amine Functional Group, StyreneCrosslinked with Divinylbenzene, Chloride Form.

Zinc chloride when combined in solution with sodium (or magnesium)chloride brine will form a divalent anionic complex of [ZnCl4]2—whichhas a direct chemical “selective” affinity for strong base anion resinand membrane media. In this form, the Zinc complex will be adsorbed ontothe media (resin or membrane) but allow other cations to pass and not beadsorbed on the media. The media is maintained in the chloride form, butwith such high levels of chloride present in the subsequent brine(sodium or magnesium chloride brine), the chloride is not affected orexchanged. Just the zinc chloride complex is adsorbed to the resin ormembrane media. The adsorption media, such as the resin, has selectiveattraction to various ions such as chloride, hydroxide, and hydrogen.When the resin goes through an ion exchange process, one ion isexchanged (ion to be removed) for the “ion form” (ion naturally on theresin). In this case, if there was “ion exchange”, chloride would bereleased into the water as the zinc was adsorbed. But since the brinehas such a high concentration of chloride in the brine, e.g., at least30,000 ppm, there is no release of the chloride. In this case, there isnot technically “ion exchange;” there is no actual exchange of ions,just adsorption.

During the rinse or “flush” step of the resin to remove the zincchloride complex from the resin or membrane, the sodium or magnesiumchloride brine is flushed from the media tank, then RO permeate waterfills the tank. This removal of the brine and replacement with low TDSwater neutralizes the valency of the complex which reverses theadsorption process, thus zinc chloride complex sloughs off the resin anddissolves into the RO water. In the flush process, a minimal amount ofRO water is utilized to maximize zinc chloride concentration in thesolution to re-form a brine. This flushed product is then blended backwith rejection brine from the high salinity RO system (sodium ormagnesium chloride brine) which forms a blended high brine solution(zinc chloride and sodium or magnesium chloride). This thenreestablishes the zinc chloride complex and thus the purificationprocess can be repeated. The zinc chloride has a natural strong osmotic“draw” which makes it beneficial as a brine draw in the forward osmosisprocess. An important feature is the use of fresh water to neutralizethe zinc chloride complex in a continual process with no requiredspecial rinse chemicals, significantly reducing the material costs inthe process.

The diluted brine draw 10 is pumped from vessels 8A, 8B into a highsalinity RO membrane system 11, with the fluid passed through themembrane constituting RO permeate water, essentially or relatively purewater. The relative percentage of RO permeate water recovered from theprocess water 3 is typically on the order of 50% to 80%.

The brine draw 12 from the RO system which did not pass through the ROmembrane is a concentrated brine draw, a high TDS fluid with TDS 250,000ppm. The brine draw 12 does not have zinc or iron), which had beenremoved by the adsorption media 8 in vessels 8A, 8B. The concentratedbrine draw 12 is stored in brine storage tank 13, for mixing with zinc(or iron) flushed from the adsorption media during a rinse cycle. Thestorage tank may include a mixer and optional heat exchanger 14.

In this embodiment, a part 19 of the RO permeate water is used for rinseadsorption in a rinse cycle for the adsorption media 8 in vessels 8A,8B. The RO permeate water used for this purpose is stored in tank 11 foruse during the rinse cycle.

During the rinse cycle, the vessel 8A or 8B is isolated from the pumps 7and 9 by valves of the vessel controls 23. The sodium or magnesium-basedbrine (or acid) is drained from the isolated vessel, either to the brinestorage tank or pumped to the RO. Permeate product water 19 stored intank 20 (or fresh water from another source) is released into and fillsthe isolated vessel through control valve 22, reversing the multivalentcondition of the zinc (or iron) complex previously adsorbed onto themedia in the isolated vessel. The media releases the zinc (or iron)brine which is dissolved back into the permeate water (or fresh or tapwater). During the rinse cycle, the water released into the vessel 8Amay be allowed to rest in contact with the media. An optional step is torecirculate the permeate water over the media to minimize water used inthe process and increase zinc (or iron) concentration in solution. Afterthe cycle is complete, with the zinc in solution in the water, theresulting brine is released from the isolated vessel by operation ofvessel controls 26 (essentially a three-way valve) into tank 13 formixing with the concentrated brine draw 12. Now, to revert to thepurification mode for the system, valve 22 is closed, and vesselcontrols reconnect the pump 7 to the input of the isolated vessel and topump 9, and pumps 2, 7, 9 and 15 are activated. The resulting brine 16from tank 13 is a concentrated brine draw containing a Zinc or ironcomplex and other salts.

The zinc-based (or iron) removal media vessels 8A and 8B are designed tobe in a “dual”, “twin”, or “multiple train” mode where one vessel isonline and operational while the other vessel (s) is/are regeneratedthen put back into a “standby” ready-for-use condition. There is acontinuous flow of zinc-based (or iron) concentrate waste from the rinseprocess thus the brine draw is optimally recycled.

The tank 13 may include a heat exchanger 14 for heating the brine ifnecessary, and a cooling heat exchanger 16 may be located downstream ofthe heat exchanger. The purpose of the cooling heat exchanger is to cooldown the brine draw prior to entering the forward osmosis membrane tominimize mineral fouling on the forward osmosis membrane. This brinedraw loop is a continuous processing loop with multiple pumps. The pumpsbuild up heat over time, so a cooling step controls fluid temperaturewhich in turn minimizes the potential for mineral scale fouling on theFO membrane.

To recover clean water from high brine or highly saline water streamssuch as sea water, manufacturing waste streams, produced water orfracturing flow back water, the high brine recovery or rinse system isimplemented as noted above. The treatment technology described abovesplits out the pure water thus making it available for reuse and at thesame time re-concentrates up the brine draw so the system works in acontinuous low cost, high efficiency process. This is done in a mannerthat uses a low energy strong base anion adsorption media, such as aresin, and fresh water for resin rinse. Utilizing fresh water forrinsing is an important factor because it is extremely low cost.

There are many resins that can separate zinc from resin, but the morezinc to be removed, the more regeneration chemical needed which drivesup operating cost significantly. Traditional cationic resins used forzinc removal would utilize so much rinse chemical that the process wouldbe cost prohibitive. In the process described above regarding FIG. 1,the unique anionic resin removes zinc from the zinc-based brine which iscombined with another brine (or acid, like HCl); in this form the brineis multivalent thus allowing the anionic resin to have an attraction toit. When the resin goes into the rinse cycle with fresh water, thisflushes the accompanying brine from the resin which reverses themultivalency of the brine and thus the zinc-based brine is easilyremoved from the resin with just tap water. For this reason, it isimportant that the FO brine draw include or consist of a blend ofmultiple brine solutions blended together or be in combination with anacid (such as HCl). These are to include zinc chloride, zinc bromide,sodium chloride, and or magnesium chloride as examples (but not limitedto). To recover the costly brine draw material and minimize waste, astrong base anion exchange resin is used to first separate the zincbromide or zinc chloride brine salts thus leaving the effluent solutionas only pure water combined with the magnesium chloride, sodium bromide,or sodium chloride brine draw to be processed by the high salinityreverse osmosis system. The strong base anion resin is regenerated withclean, permeate water from the final step of the process. The highsalinity reverse osmosis (or nanofiltration) system is then used as thefinal processing step to produce permeate water for reuse at the sametime producing a high total dissolved solids brine to be blended withthe regenerant from the resin stage in the process.

Overall system recovery rate can be as high as 50-80% depending on theinfluent water quality and salt content, while net operating pressuresare minimal due to low fouling factors and thus optimal energyefficiency (no evaporation process required).

This process has the potential to treat incoming water streams that areover 300,000 ppm TDS and extract pure water from the stream withoutusing evaporative processes. This has yet to be achieved using any othertechnology outside of high energy cost, high operating cost, and highcapital cost evaporator technologies.

Exemplary applications for the system and process include sea waterdesalination, mining waste water treatment, produced water and frac flowback treatment, industrial waste water recycling, food processing wastewater recycling, brine concentration “weight up” processes, juiceconcentration food processing, and power plant effluent treatment.

Following is an equipment list for the system illustrated in FIG. 1:

Equipment Item List: 1) Influent Storage water tank for primary feedwater to the system; 2) Feed water pump; 3) Process water fed into FOmembrane system; 4) Forward Osmosis membrane system; 5) Effluent WasteRejection from the FO system; 6) Diluted Brine Draw containing ZincComplex (or iron) and other brine salts (example sodium chloride,magnesium chloride); 7) Media pump to Anionic media 8) Adsorption media(resin or membrane) for Zinc complex; 8A, 8B) Vessels for holding theadsorption media; 9) RO Feed pump 10) Diluted Brine Draw with No Zinc orIron Complex 11) High Salinity Reverse Osmosis system 12) ConcentratedBrine Draw with sodium or magnesium chloride only (no zinc complex 13)Brine Storage and Mix tank 14) Zinc (or Iron) Chloride Brine from BrineFlush 15) Forward Osmosis pump; 16) Cooling Heat Exchanger; 17)Concentrated Brine draw containing both Zinc (or iron) chloride andsodium (or magnesium) chloride; 18) RO Permeate Water 19) RO PermeateProduct Water for Adsorption Rinse; 20) Water Storage tank for ROpermeate and Resin Flush; 21) Pump for Resin Rinse process to neutralizezinc chloride complex; 22) Control Valve; 23) Media Vessel Controls.

Second Embodiment

FIG. 2 is a schematic diagram illustrating a second embodiment of a highsalinity water purification system. This system employs a three-stepbrine draw recycling process. The process uses the combination of astrong anionic base adsorption ion resin or strong base anion adsorptionmembrane, sometimes referred to as “media,” in addition to a capacitivedeionization system to recycle a zinc-based (or iron) brine drawcombined with a sodium or magnesium-based brine draw (or acid) (whichmay include LiCl, CaCl 2, LiCl and HCl, HCl, KCl, CsCl, NH 4Cl, and HONH3Cl). The brine draw is processed by a high salinity reverse osmosissystem for improved brine draw recycling performance, overall higherefficiency, and lower operational cost.

The system and process of FIG. 2 differs from that of FIG. 1 in therinse process. The purification cycle for the process of FIG. 2 isidentical to that of the process of FIG. 1. The process of FIG. 2utilizes an alternative adsorption media rinse.

The purpose of the capacitive deionization system is to further removepure water and thus concentrate up the flushed zinc salts removed fromthe flushing/rinsing process. This process is used in lieu of anevaporator or heat exchanger to evaporate pure water off. Capacitivedeionization is a more energy efficient method of removing pure waterwhen compared to evaporator technologies.

The capacitive deionization system 30 (FIG. 2) works as follows. Anaqueous stream containing dissolved solids (salt) is passed between twooppositely charged super capacitors (electric double layer capacitors,or EDLC). As the liquid passes through the dielectric spacer separatingthe capacitors, ions are attracted to the oppositely charged capacitorlayers. The ions leave the water within the dielectric layer, passthrough a charge specific membrane coating, and are adsorbed onto thesurface area of the carbon super capacitor. When the capacitors havefilled with ions, the polarity is reversed, and the ions are dischargedback into the dielectric spacer and removed from the system. A 3-wayvalve is situated at the outlet of the device which directs the brine 32away from the cleaned water 31.

Equipment Item List (items added to equipment of the embodiment of FIG.1): 30) Capacitive Deionization System; 31) Capacitive DeionizationPermeate; 32) Capacitive Deionization Concentrate Waste Containing Zincchloride concentrate.

The first step in processing the brine in a rinse cycle is to separatethe zinc-based brine from a sodium, magnesium-based brine, or acid(combined with pure water). After flushing with fresh, low TDS water(first step), the eluted brine is concentrated (second step) with thecapacitive deionization system 30. The sodium or magnesium-based brine(or acid) is purified with a standard high salinity RO system, thusproducing clean water and a re-concentrated brine. This re-concentratedbrine is then blended with the eluted zinc-based brine from the mediarinse and capacitive deionization processes. The combined brine solutionis then fed back to the FO membrane and is used in a continual process.

The first step is done in a manner that uses a low-energy strong baseanion exchange media (resin or membrane) and fresh water for the flush.This flushed brine from the offline media vessel 8A or 8B is thenconcentrated with the capacitive deionization (CD) system 30 to getmaximum concentration from the zinc-based (or iron) brine. The CDpermeate 31 is fed back to the vessel controls 23 for recycling. The CDconcentrate is passed into the brine storage tank 13.

The high salinity reverse osmosis (or nanofiltration) system is thenused as the final processing step to produce permeate water for reuse atthe same time producing a high total dissolved solids brine to beblended with the capacitive deionization concentrate from the firstmedia stage in the process. Overall system recovery rate can be as highas 50-80% depending on the influent water quality and salt content,while net operating pressures are minimal due to low fouling factors andthus optimal energy efficiency (no evaporation process required).

Third Embodiment

FIG. 3 illustrates a further embodiment of a high salinity waterpurification system. This system is similar to that of FIG. 1 butincorporates two changes to enhance performance. A first change is thata caustic feed tank 24, feed line 25 and caustic chemical pump 32A areadded, with a pH sensor 31 in water storage tank 20. A pH controller 30is responsive to the pH sensor signal, to control the pump 32A to pump acaustic chemical stored in the feed tank to make the RO resin flushwater “alkaline” and have a pH in the range of 9-12. Examples of thecaustic include sodium hydroxide, potassium hydroxide, calciumhydroxide, calcium oxide, magnesium hydroxide, calcium carbonate, sodiumcarbonate, and ammonium carbonate. By slightly altering the pH of therinse water, i.e. the RO water used to rinse the resin, this helps thezinc to release from the resin in higher concentration than juststraight RO water alone, which makes the rinse water higherconcentration. By raising the pH, the changing point in which the zincchloride complex changes from anionic to cationic is altered. Thisallows the more rapid release of ions off of the resin which in turnincreases the concentration in the rinse water.

A second change incorporated in the embodiment of FIG. 3 is the additionof acid feed tank 26, acid feed line 27, acid chemical pump 32Band pHsensor 29 in the brine storage tank 13. A pH controller is responsive tosignals from the pH sensor 29 to control the acid chemical pump 32B topump acid chemical from the tank 26 to the brine storage tank 13 asneeded to control the pH of the brine in tank 13 to approximately therange 2.5 to 5.0. As the alkaline water from tank 20 flushes theadsorption media in tanks 8A, 8B, the water slowly turns acidic again.The pH of the brine in tank 13 may need to be slightly altered, byslightly lowering the pH so that the brine mixture becomes an anioniccomplex once again to that the process can be repeated. Examples of theacid chemical in the tank 26 include hydrochloric acid, sulfuric acid,phosphoric acid, muriatic acid, citric acid, sulfamic acid, carbonicacid and nitric acid.

By adding slight amounts of caustic to boost the pH of the rinse waterto make it more alkaline releases the zinc in the rinse step moreefficiently so the concentration is higher. The higher concentration ofzinc chloride is addressed by adding a slight amount of acid to thebrine in tank 13 to turn the brine mixture back to an anionic complex.

Fourth Embodiment

FIG. 4 a further embodiment of a high salinity water purificationsystem. This system is similar to that of FIG. 2 but incorporates thetwo changes to enhance performance described above with respect to FIG.3. Thus, a caustic feed system is added to the system of FIG. 2 to addcaustic as needed to the water in tank 20 to maintain the pH in therange of 9-12. The feed system includes the feed tank 24, pH controller30, pump 32A, feed line 25 [and pH sensor 31. Similarly, an acid feedsystem has been added to control the pH of the brine in tank 13 toapproximately 2.5 to 5.0. The acid feed system includes tank 26, pHcontroller 28, pH sensor 29, and acid feed line 27.

Although the foregoing has been a description and illustration ofspecific embodiments of the subject matter, various modifications andchanges thereto can be made by persons skilled in the art withoutdeparting from the scope and spirit of the invention.

What is claimed is:
 1. A high salinity water purification process forprocessing high salinity influent fluid to obtain purified water,comprising: passing a stream of the influent fluid in an input along afirst side of a forward osmosis (FO) membrane and delivering an outputstream from an output port, the influent fluid having moderate levels oftotal dissolved solids (TDS); passing a stream of a concentrated brinedraw from an input along a second side of the forward osmosis membrane,the concentrated brine having high levels of TDS, the concentrated brinedraw including a combination of a zinc complex or an iron complex andanother salt brine or acid; the concentrated brine drawing pure waterthrough the FO membrane from the influent fluid, concentrating the levelof TDS in the output stream and diluting the concentrated brine draw;passing the diluted brine draw over an anionic adsorption media toadsorb the zinc or iron complex onto the adsorption media to provide adiluted brine draw with little or no zinc or iron complex; pumping thediluted brine draw with little or no zinc or iron complex into a highsalinity reverse osmosis (RO) or nanofiltration system to obtainpurified water on the output of the RO or nanofiltration system and anRO stream of concentrated brine draw without zinc or iron complex whichdid not pass through the RO or nanofiltration system.
 2. The process ofclaim 1, further comprising: regenerating the adsorption media byrinsing the media with an elutant including water to remove the zinc oriron complex to form a resultant brine with zinc or iron complex;combining the resultant brine with the RO brine to reconstitute aconcentrated brine draw for use in the FO process.
 3. The process ofclaim 2, wherein the elutant is fresh water.
 4. The process of claim 2,wherein the elutant is purified water from the RO or nanofiltrationssystem.
 5. The process of claim 2, wherein the anionic adsorption mediais positioned in a plurality of tanks, and wherein one of said pluralityof vessels, and wherein one vessel is operational for said step ofpassing the diluted brine draw over the anionic adsorption media whileat least another of the plurality of vessels is in a regeneration modeor in a standby, ready-for-use condition.
 6. The process of claim 2,further comprising: measuring the pH of the reconstituted brine draw;and introducing acid into the reconstituted brine draw to control the pHof the reconstituted brine draw to approximately 2.5 to 5.0.
 7. Theprocess of claim 2, further comprising: processing the resultant brineby capacitive deionization to form a capacitive deionization permeateand a capacitive deionization concentrate; combining the capacitivedeionization permeate with the diluted brine draw prior to passing thediluted brine draw over the anionic adsorption media; passing thecapacitive deionization concentrate into a brine storage tank forcombination with the concentrated brine draw.
 8. The process of claim 1,wherein the elutant is stored in a tank, and the process furthercomprises: measuring the pH of the elutant stored in the tank; andIntroducing sufficient caustic into the tank to maintain the pH in arange of 9 to
 12. 9. The process of claim 1, wherein: the influent fluidhas levels of TDS in the range of 30,000 to 150,000 ppm; and theconcentrated brine draw has levels of TDS in the range of 250,000 to500,000 ppm.
 10. A system for purifying high salinity influent fluids,comprising: a forward osmosis (FO) system comprising an FO membrane, aninfluent side input port and an influent side output port arranged on ininfluent side of the FO membrane, and a FO output side input port and aFO output side output port arranged on an output side of the FOmembrane; one or more vessels holding an anionic base adsorption mediafor removing zinc or iron complex from a brine; a reverse osmosis (RO)or nanofiltration system; the FO system configured to receive theinfluent fluid at the influent side input port and to pass concentratedfluid out the influent side output port; the RO or nanofiltration systemconfigured to receive input fluid at an input port and to passconcentrated fluid which did not pass through a membrane of the RO orthrough the nanofiltration system at an output port, and purified fluidwhich has passed through the RO membrane or nanofiltration system; arecirculating brine flow path; a concentrated brine draw containing zincor iron complex and another salt brine or acid pumped into the FO outputside input port, the concentrated brine draw having a level of totaldissolved solids (TDS) higher than the TDS level in the influent fluid;a pump for pumping the concentrated brine draw through the FO systemfrom the FO output side input port to the FO output side output port,wherein pure water is drawn through the FO membrane to dilute theconcentrated brine draw; the recirculating brine flow path passing fromthe FO output side output port to the one or more vessels to remove thezinc or iron complex from the diluted concentrated brine to the RO ornanofiltration system and then to the FO output side input port, thediluted concentrated brine is in a multivalent form, allowing theanionic adsorption media to have a strong natural attraction to it. 11.The system of claim 10, further comprising a rinse system for rinsingthe adsorption media with an elutant containing water in a rinse cycle,the rinse system comprising: a brine storage tank in fluid communicationwith the one or more vessels; an elutant source; a valve system forpassing elutant into one of the one or more vessels from the elutantsource to rinse the adsorption media to remove the zinc or iron complexfrom the anionic adsorption media; a brine storage tank for storingbrine from the rinsing including the zinc or iron complex; a mixer formixing the stored brine with the concentrated fluid from the RO ornanofiltration system to pass into the brine recirculation path.
 12. Thesystem of claim 11, wherein the elutant is fresh water.
 13. The systemof claim 11, wherein the elutant is purified water from the RO ornanofiltration system.
 14. The system of claim 11, wherein said one ormore vessels comprises a plurality of vessels, and wherein one vessel isoperational for passing the diluted brine draw over the anionicadsorption media while at least another of vessels is in a rinse cycleor in a standby, ready-for-use condition.
 15. The system of claim 11,further comprising: a sensor for measuring the pH of the reconstitutedbrine draw; an acid feed tank for storing an acid; a pump forintroducing acid from the tank into the reconstituted brine draw tocontrol the pH of the reconstituted brine draw to approximately 2.5 to5.0.
 16. The system of claim 11, further comprising: a capacitivedeionization system for processing the resultant brine to form acapacitive deionization permeate and a capacitive deionizationconcentrate; the capacitive deionization permeate combined with thediluted brine draw prior to passing the diluted brine draw over theanionic adsorption media; the capacitive deionization concentrate passedinto a brine storage tank for combination with the concentrated brinedraw.
 17. The system of claim 10, further comprising: an elutant tankholding the elutant; a caustic tank for holding a caustic; a sensor formeasuring the pH of the elutant stored in the elutant tank; and a pumpfor Introducing sufficient caustic from the caustic tank into theelutant tank to maintain the pH of the elutant in a range of 9 to 12.18. The system of claim 10, wherein: the influent fluid has levels ofTDS in the range of 30,000 to 150,000 ppm; and the concentrated brinedraw has levels of TDS in the range of 250,000 to 500,000 ppm.
 19. Ahigh salinity water purification process for processing high salinityinfluent fluid to obtain purified water, comprising: passing a stream ofthe influent fluid in an input along a first side of a forward osmosis(FO) membrane and delivering an output stream from an output port, theinfluent fluid having moderate levels of total dissolved solids (TDS);passing a stream of a concentrated brine draw from an input along asecond side of the forward osmosis membrane, the concentrated brinehaving high levels of TDS, the concentrated brine draw including acombination of a zinc complex or an iron complex and another salt brineor acid; the concentrated brine drawing pure water through the FOmembrane from the influent fluid, concentrating the level of TDS in theoutput stream and diluting the concentrated brine draw; passing thediluted brine draw over an anionic adsorption media to adsorb the zincor iron complex onto the adsorption media to provide a diluted brinedraw with little or no zinc or iron complex; pumping the diluted brinedraw with little or no zinc or iron complex into a high salinity reverseosmosis (RO) or nanofiltration system to obtain purified water on theoutput of the RO or nanofiltration system and an RO stream ofconcentrated brine draw without zinc or iron complex which did not passthrough the RO or nanofiltration system.; regenerating the adsorptionmedia by rinsing the media with an elutant including water to remove thezinc or iron complex to form a resultant brine with zinc or ironcomplex; combining the resultant brine with the RO brine to reconstitutea concentrated brine draw for use in the FO process; and wherein theinfluent fluid has levels of TDS in the range of 30,000 to 150,000 ppm;and the concentrated brine draw has levels of TDS in the range of250,000 to 500,000 ppm.